Telephone relay or repeater.



E. #GRISSINGEIL TELEPHONE RELAY OR'REPEATER.

atented Oct. 31, i916.

8 SHEETS-SHEET l wv@ :f1/m

APPLxcATmN man APR.21.1 910.

@25g/fvg @Hozmu www 1mi-kwamen w www TELEPHONE RELAY 0R REPEATER.'

kAPPLICATION FILED Affinia?, 1910.

1 ,203,325 v Patented. Oct. 31, 1916.

8 SHEETS-SHEET 2.

E. GRISSINGER.

TELEPHONE RELAY 0H REPEATER.

APPucATxoH FILED APR.27,19|0.

1,903,325. Patented 06f. 31,1916.

8 SHEETS-SHEET 3.

E. GmssNGER. TELEPHONE RELAY 0R REPEATER..

APPLICATION FILED APILZT, I9I0.

Patented Oct. 31,1916.

8 SHEETS-SHEET 4.

` 3 Vw@ l tot WW1/Leonce i E. GRISSINGER. TELEPHONE RELAY 0R REPEATER.

APPLICATION FILED APR. 21. 1910.

Patented Oct. 31, 1916.

8 SHEETS-SHEET 5 @wi/[Menace:

E. GRISSINGER.

TELEPHONE RELAY OR HEPEATER.

Patented Oct. 31,1916.

8 SHEETS-SHEET 6 Y @Hamm m ma H. MU j, 3, W w it 1, J wwm E. GRISSINGER.

TELEPHONE RELAY 0R REPIEATEILKv APPLICATION FILED APR.27, I9I0.

A Patented 001. 31,1916.

8 SHEETS-SHEET I.

api/mennen:

l EQGRISSINQER. TELEPHONE RELAY 0R REPEATER.

VAPPLICATlON FILED APR-2?, l9l0 Patented Oct. 31,1916

A ssHEETs-SH E a @ig l5 mim? .To all wkomiz't may] concern: l

' same; Fig.` 4 is a vertical elevation oft lao ELWoon sarvssmdria, or Burman, 1, New YonxlassIGNon 'ro AMERICAN anni;nrrioim 'AND 'rumaenien coureur* consonancia or NEW YORK.

' 'iijaLiirHoNEaEnaY cameraman.,

` Apiicauon nled'apu avfielo. l serial no. s583145.

Be it k`-nown that I, ELWOOD GRISSINGR, of*v used in, connection with the coremodiiication .'Bufalo, in .the county of Erie, and in the *shown in Fig. 17; Fig. 19 Ais a diagmmmaticv State of/ New York, have inventcdacertain View ,off one of the subscribers circuits, showneW and useful Improvement in Telephone; `1ngfthe 'detailsk of' the `varran,.,en 1ent for Relays or fRepeaters, and do hereby declareffthrowmg 1nv resistance and capacity; and

of my invention isto providea relay of,y ceptional sensitivenesswhich Will magnify the electric waves to,` van 'unusual degree,`V

description'thereof. 1 A ,K l

My invention relates'to.' anamproveme V1n telephone relays or repeaters, and the 'Oblt that the following is afull, clear, andeiractj which'isfcapable ofthe very kfinest adjust-jl `r`nent,-=which avoidsthe effects yof self-indu@ is an elevational'view fof. the-same partly. section; Fig. 311s ,an end elevation yof t partused for producingone of the magnetic fields; Fig. 5 is a yertical cross-sectionof the same; Fig.. 6 is a horizontal;cross-sectionof the core of one `of the magnets used for pro-v iilucing the magnetic fields; Fig. 7 is a similar cross-section of l.another modification of the core;.Fig. 8 is a vertical crosssectionuofthe 1 parts forl supporting the variable resistance medium and armatures; Fig. 9 isaesimilar -matic :view of thejpreferredl- .e using-two relays; Fig., 13.1s.

View of another modification thereofggFi 10" is an elevation of oneI of thepats Vust-i for adjusting; the armatures; .-llris a dia'f grammatic view of the circuit arrangement, including the relay; Fig. '-12 is. a diagram;

form-offenen' a vsingle relay; lignylty `isf agrammati'c f viewof ajclosed non-grounded Icircuit"using mingle relay Fig.15",1s a `diagrammatic 'fmewjof a grounded circuit using.tvirofrelaysl ladapted'to be operatedfxls repeaterS "Fig1,6 is' 'a diagrammatic view. of,1a.subsc" used forsupplying'two relays with "t e cursubscriber's vaanMonqlaterslitent: 'Patented oct. ai, i916.

` ;grammaticview of the circuit arrangement Fig. 20 is a diagrammatic View of one of the A jets, supplied with its` own source 'ofy current. v

f`:" In'thedrawingslis a metal plate adaptedy f .to lie-attached to any suitable non-conducting support by means of screws 2. The plate 1 is 4provided with a pair of rectangularl apertures 3,- one ateither end thereof, for receivthe loweiends of permanent magnets 4.' tion and crossfcircuiting arising yin'the fteler- .A j phone"- relaysgpnow in use, andtol provide ai'ay relaywith numerousv otherl advantagsfand improvements; which=will-beset forth'in def' A-tail'in connection with the description herelinafter.. j A `I have shown certain embodiments of ply" invention fin the accompanyingljdrawiigs,

Figure-r 1 is a plan ViewV of'therelay; Fig".,2

fvnieltal casing, 5r is, provided for covering u byi'ineans of' screws 6. Each perma- VnentjIna-gnet 4 is of tlie horse-shoe type, and

v-:each' ofthe rpoles thereof vis connected lto a ypolefshoe 7 by means of a screwS. i The polehoes 7 arein turn securedV to the sidewalls he oasingoby'means of screws 9, the cas- 5 being-provided Wnth a cover 10 to pro- .er 10 is secured to the casing` by means' lowed outp'to produce a longitudinal cylindricalcayity 13. The core 12 fits loosely 'within rtheavity 13, so as to permit longitudinal adjustment thereof.V In' order to effect Said longitudinal adjustment, a screw* threaded rod `'14. is secured in an aperture 15 in the endof each of said cores, the screwthreaded end-of Vthe rod 14 being designed to engage with a screw-threaded sleeve 1G, hav- 'jin'g a cylindrical shoulder 17 for retaining j; the same within a yoke 18. A knurled handf wheellS-is made tight upon the outer end of the f! sleevev 16 to prevent said sleeve from? movingin any except aV rotary direction l `.mea-ns of screws 19tthe end vof the casing'." In order to prevent the core 12 iin the yoke 18. The yoke, 18 is securedkk eigend of 'eacliofthe pernianentinag vsaldcaslng 5 being attached to theV the upperendsof the pole-shoes '7.' The' eA ofscrews '11; In order to receive a core 12 of large diameter, the-poleshoes 7fare hole f from'turning; While it is being adjusted .in ai 'A plied with 'a Sc1'eW'20 which extends upwardly through aslot 21 in the .cover 10.

i I* Aknlirled hand-Wheel 19 'is used for readily using an extra indilctionlcoiljl ig,'.'"-1' 7;is al diagrammatic View of alcircuit arran ement adjusting'the 'core 12. For retaining .the core 12 in its adjusted position, airing 221 is provided, the lower part of Whichis at.- `tachedr to one Aside ofthe casing 5 bylneans `f longitudinal direction,y the former is supn of a screw The opposite or up er pprtion of the ring 22 is split and provi ed with two extensions 24, which are designed to b e engaged by a screw-threaded rod 25 carrying Vthe plate 27 in its` adjusted position.

upon yits end a handfoperated .wheel 26. When the wheel 26 is turned soas to bring the two extensions 24 togetherthec ore .12

is clamped in its adjusted p0sition.fMeans is also provided for preventing any longli'- tud'inal movement of the upper side of ringr 22. This comprises a plate 27 having a right-angle extension 28 extendingover said upper portion of the ring 22, and an upwardlydirected right-angle extension 29, which is adapted to receive the end of 4a screw 30 carried by a bracket 31 attached by means of a screw A32 to the cover 10. The

plate 27 has a slot 32'l to receive a'screvv 33 projecting upwardly from the-.cover 10. By this construction it will be seen'that the upper end or side of the ring 22Lmay be.' retallied against tlievface of the casing 5, by causingd the screw 30 to pull the right-angle extension 2S in the direction of thjezcasing.

The screw 33 can also be used for l retaining As shown in Figs. 5 and 6, eachlof-the cores is constructed of threepla-tesof brass 34, having interposed between the sa-me two layers f soft-iron.plates' 35 'constructed preferably of ferro-type iron.l The brass plates 34 and the soft-iron plates z35" are` secured together by transverse rivets"'\36.

. are of similar construction to the usual tele- 'lfwo recesses 37 are` provided at one endbf the core 12, adjacent to the ends of thefirn plates 35, to' receive the inner ends ofthe pole pieces 38, a screw 39 beingpr'ovided 'for clamping the pole pieces 38 inposition.' The other ends of the pole pieces 38 pass through coils 40, one coil 40 beingiprovided for each of the pole pieces 38. TheI cbils phone coils. The ends of the pole pieces 38 may be protectedby a mica diaphragm.

38,to prevent the -adherence of magnetic particles.

The p\ ats described permit a mechanical adjustne` t of the core 12. I alsol provide mechanism for adjusting' ytheI magneticwfield of the parts described. Forthisfpuip'ose `I` provide the cover 1`0 of the casing' 5 with a bracket 89, which is attached to saidcover by means of screws 40% The outer end ofthe bracket 39 carries-av screw" 41, the lower end of which carries a magnetic projection 42". The parts foi producing the 'magnetic field shown at the otherend of the plate l are constructed in a similarmari-rv ner, except' that thecoils carried upon/the pole pieces therein are wound so as,to prol duce a magnetism of the opposite polarity.

AAnother modification ofthe coreisshown in Fig. 7 in which the permanent magnet 4 is entirely dispensedwitli, and "ini lieu.V

thereof an electro-1nagnet il is provided iii Lacasse the interior ofthe ogrer for producing the `magnetic field. rIIY order to accommodate the coil' 41, ya portioirof the central brass plate of the'cre 12 is slotted out for this purpose.` Inithe interior ofthe coil 41 a soft-iron'oore.'.42 is inserted, which core is clamped tothe soft-iron plates 35y screws 43 passing through the sides of t e core.A -Forreceiving the variable resistance me-v ldium,a Lboxjl 44 kis attached by means of 75 Screws 45 to the center of the plate 1. The

box 44 Aisse arable vertically at the center thereof, an Vis provided with brackets 46 for securing the parts together. In the center of the box 44 there is a c lindrical opening 47,forreivng a pair ofy constrctionl vThe rings 48 4support in recesses 49,.upon'theirinner faces afpair' of interioily screw-threaded rings 50. i Referring particularlyfto Fig. 8,t h e rings' `50 are designed to' ysupportl upon their iuteriors'an "interioi'l'v and exteriorly' screwthreadedring 5l. e interior of the vring 51 "e 11ga'ges "witli. the screwethreaded eif v tei'iors'jofwa pair o f'electrodes 52having 90 cavities' 531` in 'their faces, and apertures 54 in 'tlie ir centers.y Screws 55' ssing'through tle' rings 51j provided or holding the electrodes '52 in position; ,f The electrodes 52 may*i herotated orflongitudinal` adjustment by removingthe Asc1`fews`-5'5, and inserting through tliescre'w-holes a rodfto engage with one o ffi'th'e recesses 56 provided upon the exterior of the electrodes 52. A pair yof eX- ,j rteriorlyscrew-threaded sleeves 57, attached 100 to each otherby anfginsulating rblock 58, .fpasses through `the apertures in the elecvtrodes1-52.` f ach 'o'fthef sleeves 57 carries, adjcent to the inslating block 58, a coni Acal electrode "59, screw-threaded upon the 10,5 'exteriorf offsaid sleeve. Adjacent "to the conical electrode 59,]thesleeve 57fcarriesa fabric Jdiaphra'i'gmf` 60, supported upon -va washer; "61., `Adjacent to" the fabric diaL phragxi'r 60, ythe sleeve 57 carries'a small 110 washer2, kand adjacent to' this a mi a` lia` phragm 63."A ThefabricdiaphruginO, the washel, Aand the mica diaphragm 63 are secured in position between the Yedge ofthe sleeve l'and the ring 50.- overthesleeve 57 toy the wahe'r .62 against'the facesfof the r'liaphragin's.l ,Another nu't 65 is," screw-threaded upon the sleevej] yfonthe purpose of bowing out-- wardly;` a steel, wire. 66`- to tighten the, same. 120 n 'insulating' washer 67 separates,y the nut 65 froiI theywire' 66.4 A n insulating washer 68 is passed overftheexteriory ofY tliesleve ,57 'to-separate'an annular terminal 69 carriedffuponf'said r'sleeve and-.connected vwith 125.

rings 48 of like i nut 64 isjpas'sed 1 1 5 ositionfk The electrodesbZ and incassa key 74: being supported in projections 76 and 77 upon the face of the ring 48. Eachl end of the wire 66, therefore, passes upwardly between the projections 76 and 77. Each of the projections 76 is split at one side and provided with a screw 78, sov that fthe winding-key 74 may be retained in any adjusted position.y The rings 48 are tightly secured together by screws 79, thereby clamping all of the parts of the variable resistance chamber together. When' the variable resistance chamber is setl up, it is providedwith a quantity of granular carbon or other variable resistance medium in the chamber between the electrodes 52 and the electrodes 59.v

One yterminalof the local relayv circuit is connected to the Wire 70, While the other ter- 'minal is preferably 'connected to one of the rings 48 by means o-a binding post 80, or it is'connected to any othervconvenient portion of the conducting parts .connected to the exterior of the variable, resistance chamber.

The modification shown in Fig. 9 is constructed in a similar manner to the variable resistance chamber shown in Fig. 8, but varies therefrom in the following particulars: Instead of providing the variable yresistance chamber with thetwo external electrodes 52, a singleexternal electrode 8l is provided. This being the case, the ring 5l i and the screws A, 55,.,are entirely dispensed with. The wir""66""in this instance are bowed inwardly instead; of outwardly, and

as a consequence, the nut and insulating washer 67 are dispensed with. j

The modification shown in Fig. 8 is pref- V erable, inasmuch 'as the sleeves 57 and interp'osed insulating block 58 are adapted bet ter to withstand a compressing strain than a,

tensile strain.

. The operation of. the parts described is follows: The cores 12 containing the iron4 55, plates or laminations 35, which plates or laminations approach ver, closely but`v do not touch the pole-shoes 7, are adjusted longitudinally by means of the hand-wheellil until the poleLpieces 38 approach very,v

'Wavewhich will cause the armature 7l at closely ,t0 but do not touch the armatures 7l. During this adjustment of the cores 12, the rings 22 are loosened by turning the screws 26.: When the vcores 12 have been moved4 into their' proper positions, the rings 22 arel tightened upon the same-by turning the i .5 wheels 26 in the oppositd direction. This arrangement constitutes what .might Abe termed an kopen. magnetic circuit, which is the ideal circuit wherean iron dore is to be excited by currents of a highand variable frequency. This magnetic circuit is termed 7g3 an openl magnetic circuit, inasmuch as thev iron plates 34 are maintained out of contact with'the pole-shoes .7, and as'they pole-pieces k38 are notpermitted to touch the armatures 71. In contrast with this, a closed magnetic circuit arrangement "is shown in the construction appearing in Fig. 7:. By meansof this construction, the iron plates 34, are continually magnetized, but not so strongly as in the case of the other-modiication al- 80 v ready described.

In the case of the variable resistance means shown in Fig. 8, the electrodes 52 may beadjusted to and from the electrodes 5,9 by removing the' screws 55, inserting arodin 85 one of the apertures 56, and rotating .said` electrodes 52. The fabric diaphragrn is designed yto lretain the variable resistance medium in position, while permitting the greatest ,amount of resiliency, and the mica 9o diaphragm 63 .is designed c for excluding moisture from the chamber of the variable resistance medium. 'It isnecessary 4thatthe electrodes 59, when moved tmckwardly and forwardly through the` influencent the arma-A tures 71, should'be returned quickly andy with great exactitude .to their original 'or normal positions. It is for this purpose gthat` I have provided the steel wire mechanism. In the modification shown in Fig. 8.in order to 100 adjust the parts foruse, the steel wire 66 is Wound as .tightly as possible upoiii) the windingkeys 74;, the projections 76 eng loosened and then tightened for this 'purpose. When this 'has been done the nuts 65 105 arerotated, so as to move the wire 66 outwardly, thereby tightening them more `than f would be possible merely by the rotation of the Winding-ke s 74.

The parts o 'the modification shownv in, 110

Fig. 9 are adjusted ina similar manner, ex" cept that the electrodesv 81 therein are' not@ designed to be adjusted, and except that the f wires 66 are bowed inwardly by the rotation of the armatures 71. In p racti e, the

ypols-zqgvieces 38 at one side of the inst u j ent can-loe` caused toapproach one of the'.` armatures more. closely than the pole-pieces 38 upon the other side of the instrument, in-

asmuch'as the armatures 7l are caused to'120 `vibrate only 1n one direction. It 1s to be understood, in this connection, that the windings Aof the coils ,4Q are such that a the right of the instrument to be attracted vto a greater degree toward its adjacent' polepieces 38, ,the receiving circuit being caused riable .in one direction,

" The magnetic field itself at each .tained in the exact positions which to pass through the 4coils 40 in multiple. side of the instrument may also `be adjusted by moving the screw 4:1n upwardly and downwardly, so as to cause the magnetic projection 42 to approach or recede from. th'e magnetic held. By this means I make use of a double varesistance medium, both portions of which assist each other. The various adjusting means. enable me to obtain a yvery nearly perfect adjustment of the armatures 7l in relation' to the`cores 12. At the same time the provision of the wires 66 absolutely insures that the'armatures 7l and attached parts, as well as the electrodes, will liebre-* k t ey have been caused to assume by the adjustment. A further benefit that is derived from the use of the wires 66 is the very reat degree of resiliency which is obtained, `akng the parts extremely sensitive to verV Slight changes in the magnetic fields. Still a further advantage that flows from this construction is the equalization of heat effectsr The passage of a current through a variable resistance chamber results in raising the temperature of the variable resistance medium. This causes the medium to expand and thereby force the electrodes and attached armature apart. In the construction which I have provided, on the contrary, any movement of one of the armatures 71 because of the expansion of -the variable resistance medium .adjacent thereto, will be counter-acted by asimilar expansion in the other chamber containing the variable resistance medium, inasmuch as the' current is conducted from all portions of; the` middle electrode or electrodes to the conical electrodes at all times. The circuit connections in their simplest forni are shown in detail in Fig. 11. In this figure the receiving circuit is shown as being connected to the-.coils 40 in multiple by means of wires 82. A single battery B is provided for supplying currentL to the two -local relay circuits 83 and 84, the circuits 83 and 84 having a common lead, containing the battery B, which is connected to the outer electrode 52, and with separate leads which connect with the two armatures 71.

Each of the circuits 83` and 84: includes the primary windings y? and p of an induction coil. The secondary or repeating circuit, as shown in Fig. 11, comprises two outside leads 85 and 86, conveying the current in one direction, and -a thir lead 87 conveying the current in the other direction. .The outside leads 85 and 86 include secondary windin g's s 'and s3 and s2 and s* respectively, located upon the primary coils pl and p referred to. That'is to say, each of the leads 85and 86 includes secondary coils located upon both of the induction coils connected tothe local relay ci rcuits 83 and 84, the said .secondary coils of the induction coil? being wound in duplex, the coil la of th ad 85 being of the same dimensions and located at the side kof the coil 's2 located in the lead 86, .and the same4 bein true of the coils s3 and s* of the other induction coil. By this meansexactlypthe same waves of the same length are imposed upon the two outy receiver, Trl the transmitter, BZ.,A the bell,

and C the condensers of the other circuit, being arranged as in the case of the usual Bell telephone common battery system. In the arrangement' shown in thisfigure, the two outside leads areconnected in `multiple with the coi s 40,k and are alsolconnected in the manner shown in Fig. 11, with the secondaries of the inductioncoils of the relay system. The third lead of each of the subscribers stations is connectdto the ground, and the third leady connected to the secondaries of the induction coils is also grounded. This system operates as a booster. iVhen a :message is sent from one of the subscribers 'stations the current passes through the coils 40;y andy k'avoids paing through the secondari'esjof the induction coils, for the reason that the resistance of these Ysecondaries is made so` great that the large impedance factor prevents the passage of the current. The current passing through the coils 40 causes the armatures 71` and attached electrodes to vibrate, thereby changing the resistances of the-variable resistance mediums. A s a consequence, the strengths of the. currents vwhich. pass through the two local relay circuits are "aried, thereby setting up induced currentsin the secondaries of the induction' coils. The induced and strengthened' currents or waves producedin the secondaries are "then added to and imposed upon the currents or waves passing overthe main leads `of the circuit. The current thus strengthened passes on to the subscriber at 'the'. other station. The arrangement described presumes that there is no direct current 'upon the line at the point where the relayis connected. If there shouldbe a direct current on the line at this point, a condenser 88 is interposed in each of the mainleads,' as shown in Fig.'v 13. These eondensers will prevent the passage of direct currents, but will permit the passage ofhigh frequency-electrical waves.y

soM

i BEST AVAILABLE CGP,`

In Fig. 14 I havev showny another circuit4 arrangement in which'a single Arelay is used, n

subscribers stations wou1d-pass through the h ut in which the various circuits are inducs tively instead o2 directly connected to the relay circuits. In the arran ement y'shown over line l, ,in the direction of then-now,

a Wave is induced upon va secondary 78'( ofy s a repeating coi-l'4 Re", the lines I, II,.'III and ,IV being 'provided lrespectively with le paths, one throng inductioncoils. As the secondaries of. .the

relay induction coils have suchial high-lim#- 'pedance factor, the current fg will" pass through the coils 40 in preference. #The Lresulting change Viii-the Vmagnetic,glields is atY varies .of the relay induction coils, and' as ia, f

transfrnied intoa current 1n thefsecond-l consequence, a current or Wavey 4of greater strength is imposed upon the cur-renterl 'lwave induced inthe secondary.; 87, l-.The

strengthensd'v current for AWave thenini vturn-z f induces a similar .current or .Wave in one-oi the other subscrili' Granite@ la' boos, i ,a dition `l current' for ,piave the current or Wave sent froingthe subtiene system scriloes sending station., It is advisable, that the cores of the repeating coils shown",k

lin this figure be always in a neutral magnetic condition. l, therefore, find it Vdesiri passage of alb-direct currents so Ias to main-v tain the cores of the f repeatingl acoils' y in f ga, ,centrally anagnetiolstaje land thereby' the` better to serveas a highly eflicient telephone able to insert a eondenser. in each of .the circuits I, H, HI and IV,'"to prevent the transformer. .in Fig. l5 l have shown stlll another circuit arrangement, involving the'useofca grounded return and-two independentpree' lays., This system involves the useJ of,y two subscribers stations arranged fin the esame',4 inanneras shovfnin Fig. l3,vexceptthat1the grounded leads'have been'provided with the-,- condensersfd to prevent disturbanoefroni stray electricalicurrents in the earth. VItis to he understood, however, that'instead of y ,the grounded, return, a third wire `may ybe used for this purpose inthe arramge'mentv shown in' this figure, it being-i understood that this third Wire may,.if desired', loe-one y I A ,2,08'111 the other branch, the phase/value of side oii' .a second telephone circuit'.4 Al'n this arrangement, shown inFig. 15,'eachof the I main leads of each `of thesubscribers stations is'fconnected in multiple with the coils Y y 40, lmdthe other through the seoondaries yof, therelay sfmuehfviiasuthe ,;ad.

is imposedggupona; v

' windings 201( and V202 of .the seconder" eircuit of that"r`elay,-and such reinforce cur "coil 4N201. NoneA of this reinforced Wave ,shouldr traverse the receiving coils 400i the ,with the secondaries of@ theother relay. A

current or wave coming from one of the "shown irrthisgigure, therefore, constitutes f5 4 s truelrepeater system, inasmuch as the cur-f, nttr .wave which ifs-sentent from 'one of he subscribers? station's'is caused toinduce anenti-relyilseparate current orfvvave in the I rcuitvu 'of kvthe fothet subscribers system. Iso .The Wo-I'wayfrepeatingi, system" yshown in f 1&1 corner"isosfy two relays, fsuehA ats-"al,- readyg descritta; which srs hiersans@eenk witheeachf other and with the two sub 'scribers" circuits or line' sections inf such i5 manner that yneither relay. can affect thev other.,y It will be seen that the incoming telephonie 'current Wave from', say, the left-4 hand 'subs'crbers circuit, will induce a cor# vrexslpouiding' wave inthe coil 200, which' waive w t traverse the receiving coils 40 ofthe `lefthand relay f and willv actuatel thaty relay'M without'producing any'efect up'on the'otherkl 'relay-,ftheooils 203 and 204toflthe `latter h'e-v j ingisecohdaryfcoilsasshciated with thep'ri- 95 ,maryiioircuit ofthe other'rela'y. The energirzation ofthe 'coilsiOfof the lefthand relay causesfaunnew and corresponding telephonie p current:v Wave'l to'fhe produced in "the two n foe rent '.WaveV mayl he' 'described as,l passing through"l the vwire 205 to the point of 'coni nection QOGWWhere-it'divides, a part going.

throghthe repeating v'induction coil 208 105 'backwto `the otherfendof; the originating' secondary coil 202 and a part goingfback vthrough repeating induction coil 207k to the y otherond of fthe other originatinginductionA right hand relay, inasmuchas the operation of Athe latter Wouldobviously produce coun` 'terrepetiton and; resultant-fconfusionor 'a l howling. This'is avoided'iirst by the ad- 115 "est nr reiheccilsaosfsaoefsnd2o742o1 nene "branchQso thattherre'sistan'c'zes therebridgedV between points of 'substantially 12o equal potential. By associating with the 'repeating-induction coil 207 an artificial A lineor circuit 210 having the sam'eel'eotrical characteristics as the subscrihers circuit associated with the, repeating'finduc'tion `coil 126 the 1current' in each'branch is'ibalanc'ed orA peated into the artificial line 210 from one branch, and into the right hand subscribers line from the other branch, and the current in both branches is in phase, as stated, and, of substantially e ual value, so that the rel ceivingvcoils 40 o main inactive. An set 211 is connected at the end offtheartiicial line 210, and when such line has been adjusted so as to equal thel electrical characteristics of the subscribers circuit, the operator will get through herr listeningein set the same character of, transmision asis` being experienced by the subscriber. Thus various subscribers circuits `ma be connected with the repeating inductlon coil'of one branch and readily balanced by the adjustmentof the ator can in each case ascertain. whether the vtransmission to such circuits is as it should beplate `98 having a contact-plate subscribers relay, and the relayed current.- emanating from the secondary coils 203 and-204 thereof is transformed andv repeated 'by the coils 200 and 212 to the other subscribers'cicuit andto the artificial balancing line 213 there; of, which latter, when adjusted to equal the' characteristics of the former, willresultin and relay.

relay in each` branches of the circuit through which' the 1 phase of the ,f

currentin each4 branch is balanced orequal?v l preventing reaction by the left-h It will thus be seen that the case is bridged -across or between I relayed current passes,'an`d the ized bymeans of the Irtiiicialline.

`The details kof the' means for adjustingy the artificial? lines comprise an insulating 99fadjlcent to a series of contact-studs 100 tures between to receive ,al plu the electrical circuit atlany d for introducing inductance, series lofstuds 101 adapted to'serve inlike esired point manner for introducing capacity. "Inl:

19 there is shown afdiagram of the wi of this device, 102 being a contact-plate,"103

the series ofresistance coi'ls, and' 104 being a series'of condensers'.

The diagram B repf resents the operators listening-in set,- whichk it will be noted is connected to the" artificial line through such inductance and capacity as may be introduced therein by the manipu- .l

lation of the plugs.

In Fig. 16 there is yshown another modification of the .subscribers set, whichy varies from the arrangement in general use 'in the Bell system, and whichhas already been described, inthe inclusion of an induction coil 4' 105, the primary of which is attached to the ground circuit, .and the ,secondary of which is connected across the terminals of the subscribers receiver.

the right hand relayreoperators listening-in artificial line, and tlieoper- A A f i M150 v Thecirc'uit is symmetrical. A telephonie" `cyrrent wave emanating from the right hand station actuats the rightJhandI witl a r-i to comp ete l andL another' which is in circuit ywith-y the 4ary winding 'BEST AwuLAeuscoP,r

In Fig. 17 I have shown any arrangement ofcircults whereby two relays may be provided with current'from the same battery.'

In Fig. 1,8 Van arrangement of circuit is shown by means of which the coils 41, of Fig. 7 are energized.

g.'20,sliows an arrangement of the subw-ith'electrical venergy within or near t e set, as distinguished from the arrangement in the'common batterytelephone system, such asfthe usual Bell'telephone arrangement already referred to.

scrbers set, in which each set is supplied The larrangement,

shown in Fig. 20co1nprises the grounded rre-f` turn.` In this ligure yTr is a/transmitter, B a local battery, the primary of the local induction coil, l the bell, C a condenser, R the receiver, 'a the secondary of the induction coil, of'whichv` p is the primary. Currents coming to such a station pass into primaries avrtriple wound repeating coil, the

third windings ,of which is connected with' areeiver R. The condenser C' is inserted between each side of the main line and the terminalsof the coil pp', the other terminals of' these coils being connected together and to a ground return or third wire return, as desired. l

While' yIj have Idescribed my 'invention above in detail, rI wish it to be understood that many changesmay be made therein without departing from the spirit of my invention., i f u I claim 1. A. vtelephone circuit com of subscribers stations, a re having an input circuit and rising' aKrk pair ay apparatus an output cir- `cuit said out ut circuit includin the ria g P mary of'an in uction coil, said induction coil having two secondary windings one in each branch of a duplex'circuit, f'being connected to points said input circuit ofequal potential in said branches, un artificial line, and a repeating coil in each branch, one of said coils yservingtto-repeat the. relayed current to a subscrlbers circuit, and the other to the artificial line. l, f

2. A telephone circuit com of subscribers stations,- a re ay apparatus having a, receiving coil and transmitting lic V rising a pair means, an induction coil the primary of v.

means, said' induction c oil having `a secon in each branch of a duplex-circuit,` said receiving coil being connected across branches, a artificial line, and `a repeating coil in each branch, one oil-said coils serving to repeat the relayed current to a subscrib# ers circuit, toghe artificial 3. ,A telephone circuit comprising in combination with the subscribers stations, a relay having itsreceiving coil bridgedacross equal branches of the circuit through whichl 12o l points `ofy equal'y potent1al. in said -y f i5 including an inductioncoillaving BEST AVAILABLE ocr the relayed current passes, a repeating-inl duction coil in each such branch, one'lof such coils serving to repeat the relayed message t"L 1,203,325'U u to a subscribers' circuit, and Atheol/her to' an,`v

the phase displacement at such pointsfcom` Jprising van artiicialvline inductively` assoevicted with the duplex circuit and having the,

saine electrical characteristicsfas the sub-4 scribers circuit. 1

5. Av two-Wayy repeating ycircuit compris ing in combination two subscribers circuits each-having a relay adapted "to be' actuated thereby',` each relay having an input receiv,

ing coil and an output element, the output element including an induction coil having a winding in each branch of a duplex circuit, the receiving coil of said 'relay being connect;

' ed betweenpoints 'of equal potential in the branches of the duplex' circuit of the other relay, and. means for equalizing or balancing the phase displacement at such points com- "ceiving coil connected in balanced-relation prising an artificial line inductivel'y 'associated with the duplex circuit and having the @i0 same electrical characteristics as the subscribers circuit# G. A tWoJWa'y repeating circuit compristhe branches o 2c relay, and means foreqiializing or balancing to repeat 'the relayed current to tlie':receiv-. ing subscribers, and means including' a coil i l in' the other branch and a line inductively.

associated withy such coil for neutralizing the effect branches.

7. A two-Way repeating circuit comprisin'g in combination two subscribersciicuits of phase. displacement in'said'- i each having arelay adapted to be actuated v thereby, each relay having an input receive ing coil and anoutp'ut element, the output element including an' .induction coil having a Winding in each branch of 'a duplex circuit, the receivingl coil of each'relay beingconnected betweenfpoints, of equal potential in other relay, a repeating coil in one branch adapted to repeat the relayed current to the receiving subscribers, and means including a the duplex circuit'of the' l coil in the other branch and a line inductively associated with such coil for neutralizingthe effector phase displacement in said branches. I

"8. A tele hone'repeating circuit comprisfing-two re ay instruments and means -for preventing reaction of the relays upon Y themselves, v'comprising an' artificial line adapted foradju'stment to: have the same Velectrical characteristics as one of. the subing incombination two subscribers .circuits each having a relay 'adapted to be actuated '45 tlieicby, each relay having an input element and an output element, the'output` element L 50 between poi ts of equal potential in the branches of the duplex circuit of the other relay, a repeating coil in one branch adapted scribers circuits, and an operators listeningin set connected in such artificial line Whereby the transmission to -the listening-in operator is th'c same as to the subscriberre ceiving the relayed message.

-9. A telephone repeating circuit comprising` two subscribers circuits; a vrelay 'actuated by ea'ch, and each relay having its re- With the secondary circuit of the other relay,

prising 4an artificial line having the same and means for adjusting the balance'comelectrical characteristics as a'subscribers line i and including an operators listeninginset adapted for connection at the end of such artificial balancing lline. i l

In testimony that I claim the foregoing Iliav e hereunto lset my hand.- 1 I Witnesses l CHARLES J. KELLY,

MAY E..CoRM1oK.

ELWOOD cnissi-NGER.' 

